A brassinosteroid functional analogue increases soybean drought resilience.

Drought severely affects soybean productivity, challenging breeding/management strategies to increase crop resilience. Hormone-based biostimulants like brassinosteroids (BRs) modulate growth/defence trade-off, mitigating yield losses; yet, natural molecule's low stability challenges the development of cost-effective and long-lasting analogues. Here, we investigated for the first time the effects of BR functional analogue DI-31 in soybean physiology under drought by assessing changes in growth, photosynthesis, water relations, antioxidant metabolism, nodulation, and nitrogen homeostasis. Moreover, DI-31 application frequencies' effects on crop cycle and commercial cultivar yield stabilisation under drought were assessed. A single foliar application of DI-31 favoured plant drought tolerance, preventing reductions in canopy development and enhancing plant performance and water use since the early stages of stress. The analogue also increased the antioxidant response, favouring nitrogen homeostasis maintenance and attenuating the nodular senescence. Moreover, foliar applications of DI-31 every 21 days enhanced the absolute yield by ~ 9% and reduced drought-induced yield losses by ~ 7% in four commercial cultivars, increasing their drought tolerance efficiency by ~ 12%. These findings demonstrated the practical value of DI-31 as an environmentally friendly alternative for integrative soybean resilience management under drought.

Early histological, hormonal, and molecular changes during pineapple (Ananas comosus (L.) Merrill) artificial flowering induction.

Natural flowering can cause serious scheduling problems in the pineapple (Ananas comosus) industry and increase harvest costs. Pineapple flowering is thought to be triggered by increased ethylene levels and artificial forcing of pineapple flowering is a common practice to promote flowering synchronisation. However, little is known about the early hormonal and molecular changes of pineapple flowering induction and development. Here, we aimed to analyse the molecular, hormonal, and histological changes during artificial pineapple flowering by Ethrel®48 treatment. Histological analyses of the shoot apical meristem, leaf gibberellic acid (GA3), and ethylene quantification were carried out during the first 72h after Ethrel®48 treatment. Expression profiles from ethylene biosynthesis (AcACS2 and AcACO1), gibberellin metabolism (AcGA2-ox1 and AcDELLA1), and flower development (FT-like gene (AcFT), LFY-like gene (AcLFY), and a PISTILLATA-like gene (AcPI)) genes were analysed during the first 24h after Ethrel®48 treatment. Differentiation processes of the shoot apical meristem into flower buds were already present in the first 72h after Ethrel®48 treatment. Ethrel®48 lead to a reduction in GA3 levels, probably triggered by elevated ethylene levels and the positive regulation AcGA2-ox1. AcLFY activation upon Ethrel®48 may also have contributed to the reduction of GA3 levels and, along with the up-regulation of AcPI, are probably associated with the flower induction activation. AcFT and AcDELLA1 do not seem to be regulated by GA3 and ethylene. Decreased GA3 and increased ethylene levels suggest an accumulation of AcDELLA1, which may display an important role in pineapple flowering induction. Thus, this study shows that molecular, hormonal, and histological changes are present right after Ethrel®48 treatment, providing new insights into how pineapple flowering occurs under natural conditions.

First report and molecular characterization of an isolate of papaya ringspot virus (PRSV-W) detected in pumpkin in Cuba / Primeiro relato e caracterização molecular de um isolado de papaya ringspot virus (PRSV-W) detectado em planta de abóbora proveniente de Cuba

In this work, a virus isolate collected from pumpkin plants (Cucurbita pepo L.), showing severe symptoms of mosaic and leaf deformation, grown in Cuba, was analyzed using indicator plants, electron microscopy, and phylogenetic analysis. Plants of pumpkin, cv. Caserta, inoculated with this virus isolate showed mosaic, leaf distortion and blistering symptoms, whereas papaya plants were immune and did not show any symptoms. A transmission electron microscopic examination of leaf dip preparations made from infected pumpkin leaves revealed the presence of elongated and flexuous particles, approximately 780-800 x 12 nm in size. Genomic fragments containing the coat protein (CP) and HC-Pro genes, amplified by specific primers for Papaya ringspot virus, W strain (PRSV-W), showed amino acid identities of both genes higher than 94% when compared to other PRSV-W isolates from America. In the phylogenetic tree, this virus isolate has grouped with other virus isolates from America, Australia, and India and was more distant from the Asian isolates. Taken together, the analyses allow the conclusion that this virus isolate is a W strain of PRSV, detected for the first time in Cuba.

Neste trabalho um isolado viral coletado em planta de abóbora (Cucurbita pepo L), apresentando sintomas severos de mosaico e deformação foliar, proveniente de uma lavoura localizada em Cuba, foi analisado utilizando plantas indicadoras, microscopia eletrônica de transmissão e análise filogenética. Plantas de abóbora cv. Caserta, inoculadas com este isolado do vírus mostrou mosaico, distorção foliar e bolhas, enquanto que as plantas de mamão foram imunes e não apresentaram sintoma. Exame ao microscópio eletrônico de tranmissão de telas preparadas com a técnica leaf dip, empregando o extrato de folhas de abóbora infectadas revelou a presença de partículas alongadas e flexuosas, medindo cerca de 780-800 x 12 nm. A análise de fragmentos genômicos contendo os genes da proteína capsidial (CP) e HC-Pro, amplificados por primers específicos para Papaya ringspot virus, estirpe W (PRSV -W), mostrou identidades de aminoácidos superiores a 94 % quando ambos os genes foram comparados a outros isolados americanos de PRSV -W. Na árvore filogenética, este isolado estudado se agrupou com os isolados de PRSV-W da América, Austrália e Índia, ficando mais distante dos isolados asiáticos. Tomadas em conjunto, as análises permitem concluir que este isolado viral pertence à estirpe W do PRSV, detectada pela primeira vez em Cuba.

Effects of 60 Hz sinusoidal magnetic field on in vitro establishment, multiplication, and acclimatization phases of Coffea arabica seedlings.

The influence of extremely low frequency electromagnetic fields on net photosynthesis, transpiration, photosynthetic pigment concentration, and gene expression of ribulose 1,5-bisphosphate carboxylase/oxygenase small subunit (RBCS1), during in vitro establishment, in vitro multiplication and acclimatization phases of coffee seedlings were investigated. Untreated coffee plants were considered as control, whereas treated plants were exposed to a 60 Hz sinusoidal magnetic field of 2 mT of magnetic induction during 3 min. This magnetic field was generated by an electromagnet, connected to a wave generator. The results revealed that magnetically treated plants showed a significant increase in net photosynthesis (85.4% and 117.9%, in multiplication and acclimatization phases, respectively), and in photosynthetic pigment concentration (66.6% for establishment phase, 79.9% for multiplication phase, and 43.8% for acclimatization phase). They also showed a differential RBCS1 gene expression (approximately twofold) and a decrease of transpiration rates in regard to their control plants. In conclusion, the findings suggest that the application of 60 Hz magnetic field to in vitro coffee plants may improve the seedlings quality by modifying some photosynthetic physiological and molecular processes, increasing their vigor, and ensuring better plant development in later stages.

Effects of cryopreservation of Phaseolus vulgaris L. seeds on early stages of germination.

In this work, we studied the effects of cryopreservation on various parameters of early stages of germination of Phaseolus vulgaris seeds (0, 7 and 14 days). Percentages of germination, fresh mass of different plant parts, levels of chlorophyll pigments (a, b, total), malondialdehyde, other aldehydes, phenolics (cell wall-linked, free, and total) and protein were determined. No phenotypic changes were observed visually in seedlings recovered from cryopreserved seeds. However, several significant effects of seed liquid nitrogen exposure were recorded at the biochemical level. There was a significant negative effect of cryopreservation on shoot protein content, which decreased from 3.11 mg g(-1) fresh weight for non-cryopreserved controls to 0.44 mg g(-1) fresh shoot weight for cryopreserved seeds. On the other hand, cryopreservation significantly increased levels of other aldehydes than malondialdehyde in shoots at day 7, from 56.47 µmol g(-1) for non-cryopreserved controls to 253.19 µmol g(-1) fresh shoot weight for cryopreserved samples. Liquid nitrogen exposure significantly reduced phenolics contents (free, cell-wall linked, total) in roots at day 7 after onset of germination. In general, roots were more affected by cryostorage compared with other plant parts, while leaves were the least affected. The effects of seed cryopreservation seem to decline progressively along with seedling growth.